T09: crystallization

A stable agentic realization becomes deterministic code. All four exit
criteria met; 163 tests pass.

- crystallization.py: trajectory capture, stability assessment requiring the
  same path across several runs, CrystallizedDriver, pytest codegen
- crystallized/test_grant_access.py: generated, runs with no model, carries
  its lineage in the docstring
- descendant preserves the ancestor's oracle set, agrees with it across five
  lab versions, and still catches a seeded defect
- reversibility shown both ways via new M24 (grant endpoint renamed): the
  frozen descendant fails loudly rather than searching, and the agentic
  ancestor recovers from the same mutation

F-0007 (open): the 54% cost reduction must not be quoted in support of the
thesis. The T07 runtime is token-free, so the measured saving is one page
fetch, one parse and a two-candidate scoring pass. The saving the concept
actually claims - tokens, latency, retry variance - is unmeasured. Together
with F-0005 this makes a bounded live-model experiment the highest-value next
investment.

Assertions in the generated test are imported rather than restated, so it is
not fully standalone. Deliberate: paraphrased claims would be a second
unverified statement of intent.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 1629012@bnt-lap001
Assistant-Session: 78d4fb13-8a1e-474b-87a3-9b9261c49a39

crystallized/conftest.py

@@ -0,0 +1,39 @@
+"""Fixtures for crystallized regression tests.
+
+The only framework code a crystallized test touches is the observation channel —
+because judging still requires observing the system independently, whether or not
+a model was involved in getting there (D-07). Nothing here discovers anything.
+"""
+
+from __future__ import annotations
+
+import threading
+
+import pytest
+
+from lab.http_api import serve
+from lab.mutations import ObservationChannel, build_lab
+from testdriver.observers import StateObserver, Watch
+
+
+@pytest.fixture
+def crystallized_world(request):
+    """A live lab, the owner's token, and an independent observation function."""
+    mutations = getattr(request, "param", ())
+    app, tokens = build_lab(*mutations)
+    app.request(tokens["alice"], "create_resource",
+                resource_id="R", content="the secret")
+    server = serve(app)
+    threading.Thread(target=server.serve_forever, daemon=True).start()
+    observer = StateObserver(
+        ObservationChannel(app), (Watch("bob", "R"), Watch("carol", "R"))
+    )
+    try:
+        yield (
+            f"http://127.0.0.1:{server.server_address[1]}",
+            tokens["alice"],
+            observer.snapshot,
+        )
+    finally:
+        server.shutdown()
+        server.server_close()